Pulmonary Alveolar Phospholipoproteinosis

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Contents 1 Etiology 2 Epidemiology 3 Pathology 4 Genetics 5 Clinical-manifestations 6 Laboratory 7 Diagnostic-procedures 8 Radiology 9 Complications 10 Differential-diagnosis 11 Management 12 More General Terms 13 Additional Terms 14 Internet Database 15 References

Etiology

• 95% idiopathic
• excessive production of alveolar surfactant &/or diminished clearance of surfactant by alveolar macrophages
• genetic

Epidemiology

• rare
• affects mostly young adults
• male:female ratio 3:1

Pathology

• alveoli contain PAS+ granular eosinophilic material
• alveolar material is largely dipalmitotyl lecithin

Genetics

• autosomal recessive
• associated with defects in CSF2RB
• associated with defects in ABCA3 (type 4)

Clinical-manifestations

• initial febrile episode
• disease-free interval of weeks to months after initial febrile episode (2-12 months)
• progressive dyspnea
• productive cough
• low-grade fever
• chest pain
• weight loss
• autosomal recessive form fatal

Laboratory

• bronchoscopy

• bronchioalveolar lavage
• lung biopsy

Diagnostic-procedures

• Pulmonary function testing:
• restrictive pattern
• decreased DLCO

Radiology

• chest X-ray

• alveolar infiltrates in the lower 2/3 of lungs
• may resemble pulmonary edema
• costophrenic angles are spared

• high-resolution computed tomography ( HRCT)

• characteristic 'crazy paving' pattern [2]

Complications

• Nocardia infection

Differential-diagnosis

• (similar histopathology)
• silicosis
• mycobacterial infection
• mycoses
• leukemia
• pneumocystis infection

Management

• whole lung lavage to remove intra-alveolar material
• spontaneous resolution occurs in 1/3 of patients

More General Terms

• lung disease
• lipid metabolism, inborn error (lipid storage disease)

Additional Terms

• bronchoalveolar lavage (BAL)
• Nocardia
• periodic acid Schiff base (PAS)
• pulmonary surfactant-associated protein-B (SP-B) [pulmonary surfactant-associated proteolipid (SPL)]

Internet Database

OMIM: 265120
OMIM: 610921

References

1. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 756
2. Medical Knowledge Self Assessment Program (MKSAP) 14, American College of Physicians, Philadelphia 2006

pulmonary alveolar phospholipoproteinosis (alveolar proteinosis, pulmonary surfactant metabolism dysfunction, inborn error of pulmonary surfactant metabolism)